godot/scene/3d/vehicle_body_3d.h

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/*  vehicle_body_3d.h                                                    */
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#ifndef VEHICLE_BODY_H
#define VEHICLE_BODY_H

#include "scene/3d/physics_body_3d.h"

class VehicleBody3D;

class VehicleWheel3D : public Node3D {
	GDCLASS(VehicleWheel3D, Node3D);

	friend class VehicleBody3D;

	Transform m_worldTransform;
	Transform local_xform;
	bool engine_traction = false;
	bool steers = false;

	Vector3 m_chassisConnectionPointCS; //const
	Vector3 m_wheelDirectionCS; //const
	Vector3 m_wheelAxleCS; // const or modified by steering

	real_t m_suspensionRestLength = 0.15;
	real_t m_maxSuspensionTravelCm = 500.0;
	real_t m_wheelRadius = 0.5;

	real_t m_suspensionStiffness = 5.88;
	real_t m_wheelsDampingCompression = 0.83;
	real_t m_wheelsDampingRelaxation = 0.88;
	real_t m_frictionSlip = 10.5;
	real_t m_maxSuspensionForce = 6000.0;
	bool m_bIsFrontWheel = false;

	VehicleBody3D *body = nullptr;

	//btVector3	m_wheelAxleCS; // const or modified by steering ?

	real_t m_steering = 0.0;
	real_t m_rotation = 0.0;
	real_t m_deltaRotation = 0.0;
	real_t m_rpm = 0.0;
	real_t m_rollInfluence = 0.1;
	real_t m_engineForce = 0.0;
	real_t m_brake = 0.0;

	real_t m_clippedInvContactDotSuspension = 1.0;
	real_t m_suspensionRelativeVelocity = 0.0;
	//calculated by suspension
	real_t m_wheelsSuspensionForce = 0.0;
	real_t m_skidInfo = 0.0;

	struct RaycastInfo {
		//set by raycaster
		Vector3 m_contactNormalWS; //contactnormal
		Vector3 m_contactPointWS; //raycast hitpoint
		real_t m_suspensionLength = 0.0;
		Vector3 m_hardPointWS; //raycast starting point
		Vector3 m_wheelDirectionWS; //direction in worldspace
		Vector3 m_wheelAxleWS; // axle in worldspace
		bool m_isInContact = false;
		PhysicsBody3D *m_groundObject = nullptr; //could be general void* ptr
	} m_raycastInfo;

	void _update(PhysicsDirectBodyState3D *s);

protected:
	void _notification(int p_what);
	static void _bind_methods();

public:
	void set_radius(real_t p_radius);
	real_t get_radius() const;

	void set_suspension_rest_length(real_t p_length);
	real_t get_suspension_rest_length() const;

	void set_suspension_travel(real_t p_length);
	real_t get_suspension_travel() const;

	void set_suspension_stiffness(real_t p_value);
	real_t get_suspension_stiffness() const;

	void set_suspension_max_force(real_t p_value);
	real_t get_suspension_max_force() const;

	void set_damping_compression(real_t p_value);
	real_t get_damping_compression() const;

	void set_damping_relaxation(real_t p_value);
	real_t get_damping_relaxation() const;

	void set_friction_slip(real_t p_value);
	real_t get_friction_slip() const;

	void set_use_as_traction(bool p_enable);
	bool is_used_as_traction() const;

	void set_use_as_steering(bool p_enabled);
	bool is_used_as_steering() const;

	bool is_in_contact() const;

	void set_roll_influence(real_t p_value);
	real_t get_roll_influence() const;

	real_t get_skidinfo() const;

	real_t get_rpm() const;

	void set_engine_force(real_t p_engine_force);
	real_t get_engine_force() const;

	void set_brake(real_t p_brake);
	real_t get_brake() const;

	void set_steering(real_t p_steering);
	real_t get_steering() const;

	String get_configuration_warning() const override;

	VehicleWheel3D();
};

class VehicleBody3D : public RigidBody3D {
	GDCLASS(VehicleBody3D, RigidBody3D);

	real_t engine_force = 0.0;
	real_t brake = 0.0;

	real_t m_pitchControl = 0.0;
	real_t m_steeringValue = 0.0;
	real_t m_currentVehicleSpeedKmHour = 0.0;

	Set<RID> exclude;

	Vector<Vector3> m_forwardWS;
	Vector<Vector3> m_axle;
	Vector<real_t> m_forwardImpulse;
	Vector<real_t> m_sideImpulse;

	struct btVehicleWheelContactPoint {
		PhysicsDirectBodyState3D *m_s = nullptr;
		PhysicsBody3D *m_body1 = nullptr;
		Vector3 m_frictionPositionWorld;
		Vector3 m_frictionDirectionWorld;
		real_t m_jacDiagABInv = 0.0;
		real_t m_maxImpulse = 0.0;

		btVehicleWheelContactPoint(PhysicsDirectBodyState3D *s, PhysicsBody3D *body1, const Vector3 &frictionPosWorld, const Vector3 &frictionDirectionWorld, real_t maxImpulse);
	};

	void _resolve_single_bilateral(PhysicsDirectBodyState3D *s, const Vector3 &pos1, PhysicsBody3D *body2, const Vector3 &pos2, const Vector3 &normal, real_t &impulse, const real_t p_rollInfluence);
	real_t _calc_rolling_friction(btVehicleWheelContactPoint &contactPoint);

	void _update_friction(PhysicsDirectBodyState3D *s);
	void _update_suspension(PhysicsDirectBodyState3D *s);
	real_t _ray_cast(int p_idx, PhysicsDirectBodyState3D *s);
	void _update_wheel_transform(VehicleWheel3D &wheel, PhysicsDirectBodyState3D *s);
	void _update_wheel(int p_idx, PhysicsDirectBodyState3D *s);

	friend class VehicleWheel3D;
	Vector<VehicleWheel3D *> wheels;

	static void _bind_methods();

	void _direct_state_changed(Object *p_state) override;

public:
	void set_engine_force(real_t p_engine_force);
	real_t get_engine_force() const;

	void set_brake(real_t p_brake);
	real_t get_brake() const;

	void set_steering(real_t p_steering);
	real_t get_steering() const;

	VehicleBody3D();
};

#endif // VEHICLE_BODY_H